Worldwide, railways provide one of the most common ways of transporting cargo and passengers. As used herein "railways" includes above-ground as well as underground systems of tracks and related facilities. Typically a system of tracks guide and support a train-type vehicle formed of a series of cars. Various track configurations are employed. Examples include:
metal rails on cross ties, PA1 metal rails on slabs, and PA1 concrete or steel guide ways. PA1 TM$--Burlington Northern Railroad PA1 MARPAS & Mini-MARPAS--British Rail PA1 ECOTRACK--European Rail Research Institute (ERRI) PA1 1. Prior art maintenance programs focus on predicting maintenance needs based on assumed maintenance strategies and economic analysis. Each necessarily uses a database which includes certain selected and sometimes incomplete items such as maintenance history, traffic patterns, and track geometry as a measure of condition. Computer models substitute for maintenance personnel and limit their involvement in determining maintenance needs and performing cost evaluations. As a result: PA1 2. Prior art maintenance programs analyze predefined discrete sections of track. The selection of a discrete section is typically based on track features and usage within which performance is assumed to be uniform so that the same maintenance would be applied throughout the section. Each predefined section is treated as being uniform in condition; i.e., an average of the track condition over the length of the section is utilized in the analysis. The sections so defined are not generally uniform as assumed and hence maintenance is often done where it is not needed and not done where is needed, i.e., maintenance is not optimally performed. PA1 3. Track performance is in essence represented by longevity of track geometry and extent of required maintenance to meet traffic demands and safety regulations. Many factors influence track performance such as traffic, track features, terrain, drainage conditions, and weather. For proper track maintenance management these factors need to be correlated and studied by persons responsible for maintenance planning. These factors are often not recorded or difficult to access. Furthermore the large amount, the detailed, and the uncorrelated nature of the information make interpretation difficult even when the information is available. The ability to overcome these limitations would permit the maintenance manager to make more effective maintenance decisions even when constrained by limited available funding, and restricted track availability. PA1 1. Providing a means for establishing the required database and keeping it current, and then visually presenting and interrelating important factors needed by the maintenance manager to identify locations and nature of needed maintenance. PA1 2. Track condition is represented by a moving calculation. This treats condition measurements as a continuum and not by predefined discrete sections. This method permits the use of successive measurement runs to define the rate of change in conditions. This approach is used to identify and rank areas for maintenance and renewal independent of track features and usage. PA1 3. Graphically interrelating the influences of track performance. The relation of these influences allows the maintenance manger to correlate the factors needed to accurately assess the cause of the problems and assist in determining the appropriate corrective action. The graphical method enables the interpretation of the large amount of maintenance information and of the detailed and the uncorrelated nature of the maintenance information.
Traditionally track maintenance decisions have been made by railroad personnel using knowledge obtained from visual field inspection of track, track drawings, records of measured geometry defects (i.e., deviation of track for specified configuration), train ride characteristics reported by locomotive drivers, knowledge of recent maintenance history. Much of the relevant information influencing the decision is not in readily acceptable form and is difficult to integrate and visualize by maintenance managers. Thus the process of deciding on the optimum maintenance approach is difficult with the consequence that sub-optimal decisions usually result. Human judgment is essential, but is handicapped by the difficulty in comparing all of the influencing information. Furthermore much of the critical information is known mainly by the maintenance personnel responsible for a particular section of track. This knowledge is not readily transferred when the personnel change. Hence much of the information is lost because of the unavailability of permanent accessible records. It is evident from the above discussion that the optimization of the process of maintenance management would be greatly enhanced by a suitable means to acquire, measure, report, and integrate the relevant information. A number of software tools have been developed for planning maintenance and renewal of railway track. Examples include:
Applicants of the present invention discovered disadvantages of the prior art approaches as follows:
a) incomplete and unverified data results in incorrect or inefficient maintenance decisions, PA2 b) imperfect models caused by the complexity of real-world situations even with complete and correct data also result in unsatisfactory maintenance decisions.
The following publication relates to the subject matter of the present invention and is incorporated by reference.
Ebersohn, W., and Selig, E. T. "Use of Track Geometry Measurements for Maintenance Planning". Transportation Research Record No. 1470, Railroad Research Issues, Washington, D.C., pp. 73-83, 1994.